Preparation Of Stannous Sulfide/Carbon Composites And Their Lithium Storage Properties

Since the Industrial Revolution,energy has been an important force and material basis for the development of human society.With the proposal of China’s 14th Five-Year Plan and 2035 Vision,the concept of carbon neutrality and carbon peak has become the focus of attention of all walks of life.In recent years,due to the depletion of fossil fuels and the growth of energy demand,the demand for research on new energy storage technologies has also risen sharply.At present,lithium-ion batteries（LIBs）are widely used in various portable electric devices because of their high energy density,high working voltage（3.7～3.8 V）,good cycle performance and environmental friendliness.Among them,the anode materials of lithium-ion batteries play an important role in the energy density,rate performance and long-term service life of batteries.Due to the advantages of high specific capacity,rich resource reserves and simple preparation and production technology,stannous sulfide（SnS）is expected to become a new type of high-capacity anode material for lithium-ion batteries in the next generation.However,due to its low conductivity and huge volume expansion（>200%）during the cycle,its cycle stability is not ideal,which restricts its development.By designing and constructing the heterostructure,it can effectively improve its conductivity,increase the lithium storage sites inside the material,and prevent the precipitation of internal crystals.In addition,its conductivity and structural stability can also be significantly improved by combining it with carbon materials.Based on the above advantages,this paper uses hydrothermal,solvent,carbothermal reduction and other methods to prepare a micro-flower shape SnS@C,graphene lamellar SnS/GO/SnS@C Structure of two kinds of stannous sulfide/carbon composites.The electrochemical properties and lithium storage mechanism were studied.The main research contents and conclusions are as follows:（1）Micron flower shape composed of SnS nanoflakes was prepared by hydrothermal-dopamine（PDA）growth coating-carbothermal reduction synthesis strategy SnS@C compound material.By combining SnS nanosheets into micro flowers,this structure promotes the diffusion kinetics of Li⁺and increases the lithium storage sites of the material.The stannous sulfide microns are encapsulated in a carbon shell,which adapts to the volume change and aggregation of SnS during the charge/discharge cycle,and the connectivity coverage of the carbon shell greatly improves the conductivity of SnS nanoparticles.The results show that SnS has considerable capacity,excellent cycle stability and magnification performance in LIBs.（2）SnS₂ nanosheet was prepared by hydrothermal method and grown on ultra-thin graphene sheet,and then SnS@GO@C composite was prepared by coating and carbonizing with dopamine hydrochloride.The SnS@GO@C composite produced after carbothermal reduction treatment has a large gap between the stannous sulfide nanosheets due to the occurrence of carbothermal reduction reaction,and the collaborative optimization of graphene and carbon layer,which makes SnS@GO@C have more Li⁺storage sites,suitable ion transfer channels and higher lithium ion reaction reversibility.Besides,the conductivity of lithium ion battery is improved while the volume expansion of SnS and the broken contact between nanoparticles are limited,and the integrity of electrode structure is well maintained.As the anode material of LIBs,the charge/discharge process can have excellent cycling and rate performance.This structure provides greater possibilities for realizing potential high-capacity energy storage equipment.